Increasingly greater numbers of women of child-bearing age are entering the workforce where they are exposed to agents of unknown teratogenic potential. Chlorinated hydrocarbon solvents are widely used in industry, and preliminary studies have indicated they could have a detrimental effect on the developing fetus. These preliminary studies were not performed with reference to pregnant women workers in that inhalation exposure occurred only from days 6-15 of gestation in rats, and teratogenic analyses were conducted on term fetuses alone. We propose to examine the teratogenicity and/or embryotoxicity, transplacental carcinogenicity and behavioral effects of methyl chloroform, methylene chloride, trichoroethylene and tetrachlorethylene with reference to working populations of women. Adult female rats will be pretreated with ethanol or phenobarbital, exposed to high and low concentrations of solvents by inhalation for two weeks prior to gestation. After breeding, the dams will be exposed from days 0-16 of gestation, which approximates the first two trimesters of human development. Fetuses will be analyzed at term for embryotoxic and/or teratogenic effects, postnatally for behavioral alterations, and at 18 months for carcinogenic lesions.